The substrate materials mainly used in electrophotographic photoreceptors include cylinders made of aluminum or an aluminum alloy, substrates made of a resin coated with aluminum by vapor deposition, and belts made of stainless steel or a nickel alloy. However, there are cases where the unevenness of density which is called interference fringes occurs on the image because the substrate surface has reduced roughness and hence has a high reflectance.
This density unevenness is attributable to the phenomenon in which the writing light emitted from a laser or LED is reflected by the substrate surface and interfaces between coating films and interferes to cause the light acting on the charge-generating layer to have unevenness in intensity due to slight differences in the thickness of each coating film, resulting in sensitivity differences among parts.
A method effective in preventing the interference fringe defects is to roughen the substrate interface. Various surface-roughening techniques have been proposed (patent documents 1 to 8).
[Patent Document 1]
JP-A-2000-105481
[Patent Document 2]
JP-A-6-138683
[Patent Document 3]
JP-A-2001-296679
[Patent Document 4]
JP-A-5-224437
[Patent Document 5]
JP-A-8-248660
[Patent Document 6]
JP-A-11-327168
[Patent Document 7]
JP-A-6-138683
[Patent Document 8]
JP-A-1-123246